Improvement in clamps for holding screw-blanks



F. unman. Clamps for Holding Screw-Blanks.

Neill 7,781, Patented Feb.24.187

Fig. 1.

AMI/IOTO-L/MdGMPH/c ta)! Y/osmwzts moans) UNITED STATES PATENT Orrron FREDERICK MUTIMER, OF ROCKFORD, ILLINOIS.

IMPROVEMENT IN CLAMPS FQR HOLDING SCREW-BLANKS.

Specification forming part of .Letters Patent No. 147,781, dated February 24, 1874; application filed August 22, 1873.

machine in which bolt-blanks of different sizes can be securely held while the screw-thread is out thereon; and it consists in the construction and operation of the machine which aocomplishes the object, as will be more fully hereinafter described.

In the drawings, Figure l is a longitudinal sectional view of the machine; Fig. 2, a top or plan view. Fig. 3 is a side view of a modification of parts, and Fig. 4 is a top view of the same.

A is the bed-plate, that supports all the parts of the machine. B is a head-block secured to the bed-plate A, and grooved on each side to receive the clamping or holding jaws U. B is an upright tail-block at the rear end of bed-plate A. a is a guide-rod, centrally fixed in head-block B and tail-block B, and is firmly held in its position, when adjusted, by the holding-screws a and b, and extends forward far enough to have the head of the screw-blank w abut against it, and can be ad justed so as to receive a longer or shorter screw-blank against it, as may be desired, by moving it longitudinally. U G are the clamping-jaws, working in grooves in 'the headblocks B, having their rear ends extending back and form levers G G, and are pivoted to the head-block B by the pivot-pins I) b, on which pins they vibrate. G O are adjustable blocks attached to the rear end of the levers O in rabbets, and are beveled or rounded at 0. These blocks O are held fast to the levers O by means of the screw-bolts z z, the screw-nuts on which may be turned back, and the temper-screws yy may be turned in and bring the inner facesof the blocks nearer each other; and by the levers of the jaws being pivoted at b b, the jaws C will, when the blocks 0 are forced agiven distance apart, and after being adjusted nearer each other, be able to grasp and hold a bolt-blank of less diameter than when separated farther apart, andthen moved the same given distance. 0 is a coiled spring, its ends attached to the levers O of the clampingjaws, and serves to draw the said levers toward each other and hold the jaws 0 open, as seen in Fig. 2. c" c" are circular openings in the jaws G to receive the body of the screw-blank, and c c are countersinks in the inner side of the jaws C to receive l the enlarged head of the blank. D is a bifurcated hand-lever, the legs of which are pivoted to bed-plate A at d, and so that it can vibrate. D is a sliding block freely sliding on guide rod a, is gained out on each side, so that the legs of lever D may embrace that part of the block left by gaining, and its forward end is beveled nearly to an edge, as seen at c, Fig. 2. By this construction of lever, sliding block, the clamping jaws, and their levers, and vibrating or forcing the upper end of hand-lever D forward, it will force the sliding block D forward and between the blocks C on the levers O, and force the clamping-jaws O together or toward each other; and when a boltblank is placed in the circular opening 0 of the jaws, it will be securely clamped and firmly held to have the screw-thread cut thereon, and when so operated upon, by throwing the hand-lever back the jaws will be opened and the screw-bolt released.

A modification of this construction is seen in Figs. 3 and 4, where the sliding block is dispensed with and the lever D made in wedge form, so that its forward part will come to an edge, e, and its lower end pivoted to bed A at d, when, by forcing the top end of the lever forward, the inclined sides of the lever will strike the adjustable blocks 0, and cause the jaws G to approach each other and grasp firmly the blank that may be placed between them. In this case the adjusting-rod a would only extend into the head-block so as to be adjusted therein.

- This machineis simple, effective, easily operated, and not liable to get out of order.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, 1s

In a bolt-blank-holding device, the combination of the slot-ted head-block B, holdingjaws 0, having their levers O pivoted to the head-block, adjustable rod a, and hand-lever D, and sliding block D,-constructed and arranged to operate in the manner and for the purpose substantially as described.

1 FREDERICK MU'IIMER. Witnesses:

O. R. WISE, S. B. WILKINS. 

